Script to aid in chroot operations

chroot-tools

#!/bin/bash
# chroot-tools v1.0
# Author: Richard Nelson [email protected]
# This script sets up a chroot environment for testing on a Debian system.
# Run with sudo privileges.

VERSION="1.0"

# Default chroot directory, action, and packages
CHROOT_DIR=""
ACTION=""
PACKAGES=""
RELEASE="stable"  # Default release

# Packages required for debootstrap
REQUIRED_PACKAGES=(debootstrap)

# Function to display version
display_version() {
    echo "chroot-tools version $VERSION"
    exit 0
}

# Function to display help
display_help() {
    echo "chroot-tools v$VERSION"
    echo "Usage: sudo ./chroot-tools.sh [build|enter|remove|version] --dir <path_to_chroot> [--release <stable|testing|sid>] [--packages <packages>]"
    echo
    echo "Commands:"
    echo "  build          Set up a new chroot environment"
    echo "  enter          Enter an existing chroot environment"
    echo "  remove         Remove an existing chroot environment"
    echo "  version        Display the script version"
    echo
    echo "Options:"
    echo "  --dir, -d      Specify the target directory for the chroot"
    echo "  --release, -r  Specify the Debian release (default: stable)"
    echo "  --packages     Specify packages to install in the chroot"
    echo
    echo "Examples:"
    echo "  sudo ./chroot-tools.sh build --dir /srv/chroot/test-env --release testing --packages \"python3 curl\""
    echo "  sudo ./chroot-tools.sh enter --dir /srv/chroot/test-env"
    echo "  sudo ./chroot-tools.sh remove --dir /srv/chroot/test-env"
    echo "  sudo ./chroot-tools.sh version"
    exit 1
}

# Function to parse command-line arguments
parse_arguments() {
    while [[ $# -gt 0 ]]; do
        case $1 in
            build|enter|remove|version)
                ACTION=$1
                shift
                ;;
            -d|--dir)
                CHROOT_DIR=$2
                shift 2
                ;;
            --release|-r)
                RELEASE=$2
                shift 2
                ;;
            --packages)
                PACKAGES=$2
                shift 2
                ;;
            *)
                echo "Unknown option: $1"
                display_help
                ;;
        esac
    done

    if [[ "$ACTION" == "version" ]]; then
        display_version
    fi

    if [[ -z "$CHROOT_DIR" ]]; then
        echo "Error: Target directory is required. Use -d to specify it."
        display_help
    fi

    if [[ -z "$ACTION" ]]; then
        echo "Error: No action specified. Use 'build', 'enter', 'remove', or 'version'."
        display_help
    fi
}

install_required_packages() {
    echo "Installing required packages..."
    apt-get update
    apt-get install -y "${REQUIRED_PACKAGES[@]}"
}

create_chroot_directory() {
    echo "Creating chroot directory at $CHROOT_DIR..."
    mkdir -p "$CHROOT_DIR"
}

bootstrap_chroot() {
    echo "Bootstrapping Debian $RELEASE environment into $CHROOT_DIR..."
    debootstrap --variant=minbase $RELEASE "$CHROOT_DIR" http://deb.debian.org/debian/
}

set_chroot_hostname() {
    local hostname
    hostname=$(basename "$CHROOT_DIR")
    echo "$hostname" > "$CHROOT_DIR/etc/hostname"
    echo "127.0.1.1 $hostname" >> "$CHROOT_DIR/etc/hosts"
}

mount_filesystems() {
    echo "Mounting necessary filesystems..."
    mount --bind /dev "$CHROOT_DIR/dev"
    mount --bind /proc "$CHROOT_DIR/proc"
    mount --bind /sys "$CHROOT_DIR/sys"
}

set_chroot_runtime_hostname() {
    local hostname
    hostname=$(cat "$CHROOT_DIR/etc/hostname")
    echo "Setting runtime hostname to $hostname"
    chroot "$CHROOT_DIR" /bin/bash -c "hostname $hostname"
}

install_packages_in_chroot() {
    if [[ -n "$PACKAGES" ]]; then
        echo "Installing packages in chroot: $PACKAGES"
        chroot "$CHROOT_DIR" /bin/bash -c "apt-get update && apt-get install -y $PACKAGES"
    else
        echo "No additional packages specified. Setting up basic chroot only."
    fi
}

unmount_filesystems() {
    echo "Unmounting filesystems..."
    umount "$CHROOT_DIR/dev"
    umount "$CHROOT_DIR/proc"
    umount "$CHROOT_DIR/sys"
}

enter_chroot() {
    echo "Entering chroot environment at $CHROOT_DIR..."
    mount_filesystems
    set_chroot_runtime_hostname
    chroot "$CHROOT_DIR" /bin/bash
    unmount_filesystems
}

build_chroot() {
    if [[ -d "$CHROOT_DIR" && -f "$CHROOT_DIR/bin/bash" ]]; then
        echo "Chroot environment already exists at $CHROOT_DIR."
        exit 1
    fi

    install_required_packages
    create_chroot_directory
    bootstrap_chroot
    set_chroot_hostname
    mount_filesystems
    install_packages_in_chroot
    unmount_filesystems
    echo "Chroot environment built successfully at $CHROOT_DIR."
    echo "To enter the chroot environment, run: sudo ./chroot-tools.sh enter --dir $CHROOT_DIR"
}

remove_chroot() {
    if [[ ! -d "$CHROOT_DIR" ]]; then
        echo "Error: Chroot directory $CHROOT_DIR does not exist."
        exit 1
    fi

    read -p "Are you sure you want to remove the chroot environment at $CHROOT_DIR? [y/N] " confirm
    if [[ "$confirm" != "y" && "$confirm" != "Y" ]]; then
        echo "Aborted."
        exit 1
    fi

    echo "Unmounting any mounted filesystems..."
    umount "$CHROOT_DIR/dev" 2>/dev/null || true
    umount "$CHROOT_DIR/proc" 2>/dev/null || true
    umount "$CHROOT_DIR/sys" 2>/dev/null || true

    echo "Removing chroot directory at $CHROOT_DIR..."
    rm -rf "$CHROOT_DIR"
    echo "Chroot environment at $CHROOT_DIR has been removed."
}

main() {
    if [[ "$ACTION" == "build" ]]; then
        build_chroot
    elif [[ "$ACTION" == "enter" ]]; then
        enter_chroot
    elif [[ "$ACTION" == "remove" ]]; then
        remove_chroot
    else
        display_help
    fi
}

parse_arguments "$@"
main